Radiation-curable inkjet ink compositions are known in the art. These ink compositions comprise one or more radiation-curable components. A special class of radiation-curable inkjet ink compositions are phase change radiation-curable inkjet ink compositions. These inks are fluid at elevated temperature and become solid—even if not yet cured—at lower temperatures. These inks are typically jetted at elevated temperatures. Phase change inks may become solid or semi-solid upon cooling down on a recording medium, e.g. a sheet of paper. As a result, spread of a droplet of ink on the recording medium may be decreased and color bleeding may be prevented. An example of a phase change radiation-curable inkjet ink is a gelling radiation-curable inkjet ink. Gelling radiation-curable inkjet ink compositions typically comprise a gellant. Gellants are also known in the art as gelling agents or thickeners. Examples of gellants used in gelling radiation curable inkjet ink compositions are waxes, such as natural waxes and long chain carboxylic acids, and ketones. The presence of a gellant can cause a viscosity increase in the inkjet ink composition upon cooling of the ink composition. The viscosity increase in the ink composition should be sufficient, to adequately control droplet spreading. The use of a gelling may allow to postpone curing of the ink after applying the ink onto the recording medium.
A disadvantage of gelling inks is that liquid components may diffuse from the gelled phase to unprinted parts of the recording medium, which may result in the formation of transparent zone around the droplet. This phenomenon is called halo. Halo formation decreases the image quality of a printed image. There is a need for gelling radiation curable ink compositions that do not show halo.
It is therefore an object of the present invention to provide a gelling radiation curable ink composition that does not show halo.